YOU SAID:

hey man i just came for the cake

INTO JAPANESE

ちょっとケーキ買いに来ただけだよ

BACK INTO ENGLISH

I just came by to buy some cake.

INTO JAPANESE

ちょうどケーキを買いに来たところです。

BACK INTO ENGLISH

I just came to buy a cake.

INTO JAPANESE

私はケーキを買いに来たばかりです。

BACK INTO ENGLISH

I have just come to buy a cake.

INTO JAPANESE

私は今ケーキを買いに来たところです。

BACK INTO ENGLISH

I have just come to buy a cake.